Gear shifting mechanism



March 19, 1935. R. s. SANFORD ET AL 1,994,835

GEAR SHIFTING MECHANISM Original Fi led Dec. 11, 1931 2 Sheets-Sheet 1 INVENTOR. Far 5 57110-77170 BY Rose-R7- P 5/7656 ATT RNES March 19, 1935.

R. 8., SANFORD El AL GEAR SHIFTING MECHANISM Original Filed Dec. 11, 1931 2 Sheets-Sheet 2 INVENTOR. Ray 5 jfllVl-UA'O By ROBERT F Ems-55 ATT RNEY shifting mechanism and is of particular utility Patented Mar. 19, 1935 GEAR SHIFTING MECHANISM Roy S. Sanford, New York, N. Y., and Robert P. Breese, South Bend, Ind., assignors to Bendix Aviation Corporation, South Bend, Ind., a cor-. poration of Delaware Application December 11, 1931, Serial N0. 580,446

Renewed January 29, 1934 8 Claims.

This invention, in its broadest aspect, relate to new and useful improvements in the powe plant of an automotive vehicle.

s the engine with a drive shaft 18, the latter being r connected to the rear or drive wheels 20 through the intermediary of a conventional differential More specifically, the invention relates to gear 22. A conventional three-speeds forward and rewhen employed in connection with speed-chang verse transmission or equivalent change-speed mechanism 24 is incorporated in the driven mech- .ing and direction-reversing gearing commonly anism, and supplementing the transmission 24, used in coupling internal-combustion engines of and also incorporated in the driven mechanism, automobiles with the driving vehicle wheels or there is provided a two-speed transmission mechother propelling devices.

One object of the invention is to provide operated means for operating a two-speed trans mission mechanism, preferably mounted on the anism 26, preferably mounted on the differential power housing as disclosed diagrammatically in Figure 1.

Power means are provided for operating the difierential housing of an automotive vehicle. clutch comprsing a vacuum operated servomo- Such a mechanism is designed to supplement the ,tor, the latter comprising .a cylinder 28 secured conventional change-speed transmission by pro viding, in addition to the conventional three speeds forward and reverse driving ratios, tw

- tothe chassis and a reciprocable piston 30 operably connected to a conventional clutch pedal 0 32. A fluid transmitting conduit 34 interconnects additional driving ratios between the power plant the manifold 14 with the servomotor, a threeand the rear wheels. Thus for each 61 the two way valve 36, described in detail in an applicasettings of the supplemental transmission there tion of Victor W. Kliesrath, No. 568,082, filed are provided, by the standard transmission, .four October 10, 1931, being interposed in the fluid different gear ratios, making eight different ra tios in all.

According to one desirable construction, there ated either before or after the throttle is opened transmitting connection to control the motor in its operation of the clutch. The valve 36 is operis suggested a vacuum operated double-acting or closed respectively by a connection 38 inter servomotor mechanism controlled by a manuconnecting the valve and throttle rod 40. A lost ally operated three-way valve. prises a double-ended casing housing a unit com prising a piston and a relatively movable connecting rod, and which unit serves both' as a se The motor eommotion connection 42 is provided between the throttle 12 and rod 40 to effect this operation.

With the opening of the valve upon completely lector valve to determine the modevoi operation ating motor is energized or vacuum operated in of the motor and as the force-transmitting rea manner well-known in the art to thereby disciprocable element of the motor.

engage the clutch and upon closing the valve,

Other objects of the invention and desirable with actuationof the accelerator pedal, the motor details of construction andcombinations of parts is deenergized and the clutch permitted to enwill become apparent from a detailed descrip tion of certain embodiments of the invention, de

gage. At closed throttle the engine cylinders function .as a pump to evacuate the manifold,

scribed in detail in the following specification producing a vacuum of approximately twenty taken in conjunction with the accompanying inches of mercury.

drawings illustrating said embodiments, in which Figure 1 is a diagrammatic view disclosing the briefly,

The aforementioned structure is described only Va i us e t of the Power P a c s ituti g the instant invention, being disclosed in part in the present invention; and

the patent to Belcia, No. 1,470,272, dated October Figures 2, 3 and 4 disclose various longitudinal 9, i923, and disclosed and claimed in greater desectional views of the transmission operating tail in the application of Victor W. Kliesrath and servomotor, said motor constituting the essenc of the instant invention.

In that embodiment of the invention selected for illustration and showndiagrammaticaliy in Figure 1 there is provided a conventional inter Sanford, No. 580,434, filed December 11,

mental transmission 26 mounted on the differennal-combustion engine 10 having a throttle 12 tial housing. Such means, in brief, comprises a. and intake manifold 14. A conventional disk vacuum operated servomotor controlled by a clutch 16 comprising the usual driving and driven manually operated spring loaded three-way valve plates, or equivalent elements, servestoconnec t 43, the latter being preferably rigidly secured to releasing the accelerator pedal the clutch operinasmuch as the same forms no part of the means for operating the two-speed supplethe under side of the floor board in a position to be operated by the left foot of the driver.

Describing the aforementioned motor in greater detail, the same comprises a double-ended cylinder 44 pivotally secured to the transmission 26 at 46. A piston 48 is reciprocable within the cylinder, the hub 50 of which is slidably mounted on a piston rod 52, the latter being pivotally connected at 54 to a crank arm or lever member 56 operably connected, by rod 58, to actuate the supplemental transmission 26. The relatively movable ported piston hub 50 and rod 52 together constitute a selector valve to determine the mode of operation of the motor, as will be described in greater detail hereinafter. The rod 52 is provided with two separate bores '60 and 62, the latter being vented to the atmosphere at 64 and the former connected by a port 66 with a flexible air transmitting conduit 68, preferably connected at its other end to the conduit 34 intermediate the valve 36 and clutch operating motor. The spring pressed three-way valve 43 is incorporated in the fluid circuit provided by conduit 68,

\ pending upon the position of the piston.

The piston hub 50 is provided with slots,'72 and 74 to the left of the piston 48 and with slots '76 and '78 to the right of the piston, certain of which slots are adapted to register with certain. of slots 80 and 82, 84 and 86 in the rod 52. The motor structure also includes valve operating springs 88 and motor by fastenings 92. I

The; complete cycle of operations will now be described starting with the vehicle at rest and the engine inoperative.

Upon starting the engine with the accelerator released the vacuum induced in the manifold will at once energize the clutch operating motor to disengage the clutch, the piston 30 of the motor and its connected clutch pedal 32 moving to the positions shown in Figure 1. The control valve 36, at this time, is opened to interconnect the manifold with the clutch motor. The other control valve 43 is, at this time, closed, that is positioned to vent-the bore 60 to atmosphere, and the piston 48 is positioned intermediate the ends of the motor, as disclosed in Figure 2, registering ports. 74 and 82 and also registering ports '76 and I 84. The left compartment 94 of the motor is thus I vented to atmosphere via port 64, bore 62 and ports '74 and 82. The right compartment 96 is likewise 5 z ,ports '76 and 84. The crank 56 is atthi's time positioned as disclosed in Figure 1 to place the transmission 26in one of-its two'g'earsettings, preferably thehigher of the tw such setting is maintained by a spring pressed ball 98 adap ted 'to seatwithin detents 100 in the hub of the vented via valve- 43, port 66, bore 60 andregistered lever 56.

Assuming that it is now desired to start the car accompanied by the successive shifting into secend and high gears will effect the desired speed of the vehicle in the usual mannen Should it be desiredto change the driving ratio, assuming a fixed gear setting of the conventional transmission 24, it is merely necessary to declutch by releasing the accelerator and then open the valve 43 with the toe of the left foot. The right compartment 96 of the transmission operating motor is thus placed in communication with the manifold via ports '76 and 84, bore 60, conduit 68, valve 43, conduit 34 and valve 36, the latter being opened upon release of the accelerator. The piston 48 is thus forced to the right, to the position disclosed in Figure 3, by virtue of theevacuation of the right compartment 96 of the motor and the weight of the atmosphere acting on the left side of the piston 48. This piston movement also serves to compress spring 88 for a purpose to be described hereinafter.-

The piston hub during this movement abuts a stop 102 at the end of the rod 52 to thereby actuate the rod and its connected crank 56 to change the setting of the transmission 26. Preferably the above shift is effected while the car is free wheeling in conventional high gear, thereby stepping down the driving ratio between the engine and the rear wheels and permitting a very quick pick-up in trafllc. In order to obtain this pick-up it is, of course, necessary to again depress the accelerator to engage the clutch and speed up the engine. Obviously, however, the driving ratio might be changed by the operation of the supplemental transmission in any one of the re- I maining gear settings of the transmission 24.

The transmission control valve may now be closed by lifting the left toe to thereby actuate the selector valve mechanism heretofore referred to and prepare the motor for its next gear shifting operation. This is accomplished by the return movement of the valve piston '70 to the full line position disclosed in Figure 1, thus venting the right compartment 96 of the motor to atmosphere via the bore and registered ports '76 and 84. The compressed spring 88 then expands to move the piston 48 to the left relative to the rod 52, to the position disclosed in Figure 4, registering ports 78 and 86 and ports '72 and 80.

The piston 48 and rod 52 together constitute the aforementioned selector valve. The valve is furthermore power operated by springs 88 and 90, and which power operation is controlled by the control valve 43, the latter thereby serving the dual function of a control valve for the motor and as a control valve for the power means for actuating the'selector valve mechanism. It is also to be-noted that the piston and connecting rod of the motor effect the dual function of serving as the reciprocating element of the motorin' operating the supplemental transmission, and also serving as the selector valve mechanism.

Now when it is desired to step up the driving ratio, or rather return it'to' its original setting,

the aforementioned cycle of operations is repeated the piston 48 now moving to the left under the weight of the atmosphere acting on its right side. Upon closing or venting of the control valve 43 the selector valve mechanism is again power or spring operated to prepare for the subsequent gear shifting operation of the motor to follow.

It will be noted that the aforementioned motor may not .be operated to actuate the transmission 26 until the three-way clutch control valve 36 is opened. Such structure thus insures a disengagement of the clutch prior to the power operation of the transmission 26, which is the end desired. It is also to be noted that the accelerator serves the threefold function of controlling the eas es I t throttle, the clutch and the supplemental transmission.

There is thus provided a very simple and. compact Y power operated transmission operating mechanism including a power operated selector valve, said mechanism'cooperating with a power operated clutch and providing, in conjunction with the conventional transmission, eight different driving ratios to thereby insure the much desired flexibility of control in the operation of the vehicle.

Although this invention has been described in connection with certain specific embodiments, the principles involved are susceptible of numerous other applications that will readily occur to persons skilled in the art. The invention is, therefore, to be limited only as indicated by the scope of the appended claims.

We claim: A

1. A- vacuum operated servomotor mechanism comprising a double-ended casing member, relatively movable piston and connecting rod members, each provided with ports, said members functioning asa valve by virtue of the registering of said ports one with another, said members adapted to reciprocate as a unit within said casing during the power operation of the motor, valve means for controlling the power operation of the servomotor, and-means mounted at each end of the casing for imparting said relative movement between said rod and piston to provide a reversal of movement of the unit in eflecting its power loading function.

2. A vacuum operated servomotor mechanism comprising a double-ended casing member, relatively movable piston and connecting rod members functioning as a valve by virtue of said movement, said members provided with intercommunieating slots to effect said valve function and .adapted to reciprocate as a unit within said casing during the power operation of the motor, valve means for controlling the power operation of .the servomotor and a compressible spring mounted at, each end of the casing for imparting said relative movement between said rod and piston to provide the desired valve action to effect a reversal of movement of the unit in its power loading function.

3. A fluid operated servomotor mechanism comprising, in combination, a control valve for said mechanism, a double-ended casing, a connecting rod slidably mounted for reciprocable movement through one end wall of said casing,

said rod being provided with parallel air transmitting bores, a piston member slidably mounted on one end of said rod, said piston and rod being provided with openings, certain-of said openings adapted to register one with another depending upon the relative positions of the rod and piston, and means at each end of the casing for imparting relative movement between said rod and pieton.

4. A fluid operated servomotor -mechanism comprising, in combination, a control valve for said mechanism, a double-ended casing, a connecting rod slidably mounted for reciprocable movement through one end wall of said casing,

said rod being provided with parallel air transmitting' bores, a piston member slidably mounted on one end of said rod, said piston and rod being provided with slots, certain of said slots adapted to register one with another depending upon the relative positions of the rod and piston, and spring means ateach end of the casing for imparting relative movement between said rod and piston.

5. Power means for operating a change-speed transmission comprising a fluid operated motor,

comprising a casing member, a control valve for C said motor, relatively movable piston and connecting rod elements operatively reciprocable as a unit within said casing member, each of said elements being provided with intercommunicating ports to selectively control the direction of movement of the unit, the relative position of said elements to effect said control being determined in part by yieldable means interposed between the ends of the casing and said piston.

6. A vacuum operated double-acting servomotor comprising a double-ended casing member, a reciprocable connecting rod slidably mounted in one end of said casing, said rod being provided with parallel bores, one adapted to be alternately connected with a source of vacuum and with the atmosphere and the other communicating at all times with the atmosphere, a reciprocable piston member slidably mounted on said rod, said piston being provided with a hub portion having spaced slots, said rod being also provided with spaced slots, certain of said slots in the piston hub and in the rod registering, with the 4 "l. A vacuum operated servomechanism comprising a motor unit including a double-ended casing member, valve means for controlling the influx and eiilux of apower fluid to and from said casing, a combined power and selector valve unit mounted for reciprocable movement within said casing, and means within said casing for operating said unit as a selector valve.

8. A double-acting vacuum operated servomechanism comprising a motor unit including a double-ended casing member, valve means for controlling the influx and efllux of a power fluid to and from said casing, a combined power and selector valve unit mounted for reciprocable movement within said casing, said unit comprising members relatively movable with respect to each other, and means within said casing for operating said unit as a selector valve, said means being under the control of said aforementioned valve means.

' ROY S. SANFORD.

ROBERT P. BREESE. 

